Lung cancer originates when cells in the lung tissue grow uncontrollably, typically in the air passages. This abnormal growth forms a tumor, which can interfere with the lung’s normal function. Understanding how lung cancer can spread from its initial location is important for patients and their families.
Understanding Metastasis from Lung Cancer
Metastasis describes the process where cancer cells detach from the primary tumor and travel to other parts of the body. These cells can invade surrounding healthy tissues or enter the bloodstream or lymphatic system. Once in these systems, they can travel to distant organs and establish new tumors, known as metastases.
This process marks a more advanced stage of cancer, as the disease is no longer confined to its original site. The presence of metastasis indicates that the cancer has become systemic, affecting more than just the lung.
Common Sites of Lung Cancer Spread
Lung cancer can spread to various organs, but it most frequently metastasizes to specific sites. These include the brain, bones, liver, adrenal glands, and other parts of the lung itself. The rich blood supply and lymphatic drainage in these areas contribute to their common involvement in metastatic disease.
The brain is a common destination for lung cancer cells, with approximately 16% to 20% of lung cancer patients developing brain metastases. This can be due to the brain’s extensive blood supply, which provides an accessible route for circulating cancer cells. Once in the brain, these cells can establish new tumors.
Bones are also frequently affected, with bone metastases occurring in about 30% to 40% of people with advanced lung cancer. Lung cancer cells can travel through the bloodstream to various bones, including the spine, ribs, pelvis, and long bones of the limbs.
The liver is another prevalent site for lung cancer metastasis. Cancer cells can reach the liver through the bloodstream, where they can then multiply and form secondary tumors. Liver metastases are particularly common in small cell lung cancer (SCLC).
Adrenal glands, small hormone-producing glands located above the kidneys, are also common sites for lung cancer spread. Adrenal metastases are common in people with non-small cell lung cancer.
Lung cancer can also spread within the respiratory system to other parts of the same lung or to the contralateral (other) lung. This local or regional spread often occurs through direct invasion or via the lymphatic system within the chest.
Recognizing Symptoms of Metastatic Lung Cancer
The symptoms associated with metastatic lung cancer depend on the specific location where the cancer has spread. When lung cancer metastasizes to the brain, individuals may experience symptoms such as headaches, seizures, changes in vision, or weakness in an arm or leg. Confusion, memory problems, or personality changes can also occur.
When the cancer spreads to the bones, pain is a primary symptom, often described as a dull ache that can worsen at night or with movement. Bones may also become weaker and more prone to fractures. If the spine is affected, it can lead to nerve compression, causing numbness or weakness in the limbs.
Metastasis to the liver can manifest with symptoms like abdominal pain or discomfort, particularly on the right side. Other signs may include nausea, poor appetite, weight loss, and jaundice, which is a yellowing of the skin and eyes. A swollen abdomen may also be present.
Spread to the adrenal glands often causes no noticeable symptoms. However, if symptoms do occur, they can be general, such as fatigue, weakness, loss of appetite, or abdominal pain.
If lung cancer spreads to other parts of the lung, symptoms can include a new or worsening cough and increased shortness of breath. These symptoms are often similar to those of the primary lung tumor. It is important to note that these symptoms are not exclusive to cancer and warrant a medical evaluation to determine their cause.